Should be done often because we will be able to see that the participants understand the content taught? If the participants do not have a good score so we can improve our teaching.
Should do often, because we can see that the students understand the content taught or not. If students do not score well. We were able to improve our teaching.
Should do frequently because we see that the students understand the content of teaching? If students your grades are bad. We will be able to improve our teaching.